A conventional solar cell module includes a plurality of solar cells that is arranged in the form of a flat plate. The solar cells are coated with a cell protection member that is made of flexible resin, such as EVA (ethylene-vinyl acetate copolymer). A surface protection member that is made of, for example, tempered glass, is bonded onto the top surface of the cell protection member. By virtue of such a structure, the solar cell module has the structural strength required as a building material.
Solar cell modules that have more structural strength than the above-described conventional solar cell module are known in the art. There has been known a solar cell module in which a solar panel, a heat insulator arranged on the back surface of the solar panel, and a metal plate arranged on the back surface of the heat insulator are stacked in layers via adhesive layers (see, for example, Patent document 1).    Patent document 1: Japanese Patent Application Laid-open No. H09-119202 (page 4, FIG. 1)